What You Did: Stayed up till the birds started singing to finish Anna Karenina and meet your book-club deadline. Today you’re groggy, your head’s pounding, and you can barely focus.

Now What? Try to sneak in some rest, and turn to energy-boosting foods and drinks.

Take a 20-minute nap, or two 10-minute ones. “You can’t make up for lost sleep, but you can grab some new sleep,” says Georgia Witkin, Ph.D., director of the stress program at the Mount Sinai School of Medicine, in New York City. “When you’re exhausted, you’ll drift off for milliseconds throughout the day,” she adds. Short naps can reduce the number of those micro-naps.

Eat to stay alert. Try protein: eggs in the morning, lean meat or cheese at lunch and dinner. Avoid simple carbs, such as white bread, pastries, and candy, which will cause blood-sugar spikes.

Sip, don’t gulp, your coffee or tea. There’s plenty of proof that caffeine can improve concentration, but its eye-opening effects work best in small doses — two ounces of coffee or four of tea every hour. Quit about six hours before bedtime so you don’t interfere with another night’s sleep.